Method and apparatus for lifting and securing a concrete panel in place above a road bed

ABSTRACT

An apparatus to be embedded within a precast concrete panel or slab to enable the panel to be lifted, moved to a road bed, and secured in place above the road bed. A lifting apparatus is embedded at each corner of the panel. Each apparatus has a hollow threaded sleeve extending through the panel to receive a removable threaded lifting bolt by which to establish a lifting point at which a lifting force is applied to lift and position the panel on support blocks seated on the road bed. When the threaded lifting bolt is removed from each hollow threaded sleeve, grout is pumped through the panel by way of the hollow sleeve to fill the space established by the support blocks between the panel and the road bed. The method and apparatus have particular application during construction or repair of a roadway.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a method and to an apparatus to be embedded within a precast concrete panel or slab to enable the panel to be lifted from a transport, lowered towards a road bed, and secured in place above the road bed. The apparatus has particular application in roadway construction and/or repair where several panels must be laid end-to-end and/or side-by-side one another.

2. Background Art

As new communities are built, it is essential to have a roadway system to link each community with neighboring communities. Therefore, a series of highways and freeways are constructed to support vehicular traffic. A common technique for building such roadways is to lay a number of heavy precast concrete panels or slabs end-to-end and side-by-side one another. However, all of the panels must be reliably secured in place and made level with respect to one another to establish a smooth and continuous driving surface.

The foregoing is typically accomplished by grading the road bed upon which each concrete panel will be laid. The process of grading requires the availability and deployment of road grading machinery and the manpower to operate the machinery. Grading the road bed must be relatively precise so that adjacent panels will all be aligned with one another at approximately the same elevation above the road bed. Then, each panel must be secured in place so that it is unlikely to shift in response to being exposed to weather conditions and physical forces over time. Where an existing roadway is being repaired and replaced, the road work usually occurs at night and requires that the roadway be closed to traffic. In this case, the new concrete panels must be installed and retained quickly so that the repaired roadway can reopen the next morning. However, having to first precisely grade the road bed before the panels can be laid adds to the labor force, raises the corresponding construction costs, and increases the time necessary to complete the job. What is even more, the completion time and cost are further increased, because different apparatus are required to be carried by the conventional pre-cast concrete panel to enable the panel to first be lifted and moved to the road bed and then fixed in place alongside adjacent panels.

Reference may be made to patent application Ser. No. 13/594,604 filed Aug. 24, 2012 for an example of an apparatus to be embedded in a precast concrete panel to enable the panel to be lifted, laid upon a road bed, and elevated above the road bed to be made level with adjacent panels.

SUMMARY OF THE INVENTION

In general terms, a lifting and grout delivering apparatus is disclosed to be embedded within a precast concrete panel or slab to enable the panel to be lifted off its transport, lowered towards a road bed, and secured in place above the road bed to be held stationary with respect to adjacent panels that are employed during the construction and/or repair of a roadway. In accordance with the preferred embodiment, a lifting and grout delivering apparatus is embedded near each corner of the concrete panel while the panel is being cast in order to establish convenient and reliable lifting points at which the panel is relatively quickly and easily lifted.

The lifting and grout delivering apparatus includes a hollow, cylindrical threaded sleeve that extends through the panel between the top and bottom thereof. A pair of retaining bars are bent around the sleeve to help anchor the sleeve in place within the precast panel. A threaded end cap is rotated into removable mating engagement with the top of the threaded cylindrical sleeve.

Prior to moving the concrete panel from its transport to the road bed, a set of corner support blocks (e.g., shims) are laid on the road bed so that the panel will be supported above the road bed by the support blocks. The end cap is now removed from the cylindrical sleeve of the lifting and grout delivering apparatus. A hoisting cylinder having a hoist coupler pivotally connected thereto is positioned on top of the panel, and a threaded lifting bolt is inserted through the hoist cylinder and rotated into detachable connection with the threaded sleeve of the lifting and grout delivering apparatus embedded within the precast panel. The hoist coupler and lifting bolt create a lifting point at which a crane can engage and lift the panel from its transport for relocation above the road bed so as to rest upon the support blocks. The crane is then detached from the lifting point, and the lifting bolt is rotated out of its connection with and removed from the sleeve. Next, a supply of grout or a similar curable filler material is pumped through the concrete panel by way of the hollow sleeve from which the lifting bolt has been removed and grout pipes that run through the panel. The grout fills the space between the bottom of the panel resting on the support blocks and the road bed. When the grout hardens, the panel will be fixed in place above the road bed so as to be made stationary relative to adjacent panels to thereby establish a smooth and continuous roadway to support vehicular traffic.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of an apparatus for lifting and delivering grout below a precast concrete panel or slab according to a preferred embodiment of the present invention so that the slab can be fixed in place above a road bed;

FIG. 2 shows the lifting and grout delivering apparatus of FIG. 1 in an assembled configuration;

FIG. 3 shows a lifting and grout delivering apparatus like that illustrated in FIG. 2 being embedded in and located adjacent each corner of a precast concrete panel during manufacture of the panel;

FIG. 4 shows the lifting and grout delivering apparatus of FIG. 2 embedded within the concrete panel and having an end cap removably attached thereto;

FIG. 5 shows the lifting and grout delivering apparatus of FIG. 4 with the end cap removed;

FIG. 6 shows a crane applying a lifting force to the concrete panel of FIG. 5 by way of a lifting bolt detachably connected to the lifting and grout delivering apparatus in order to lift and position the panel above a road bed;

FIG. 7 shows the concrete panel of FIG. 6 being lowered towards the road bed and laid upon corner support blocks seated on the road bed;

FIG. 8 shows the concrete panel of FIG. 7 after the panel has been laid upon the corner support blocks seated on the road bed such that the panel lies adjacent another panel;

FIG. 9 shows the concrete panel of FIG. 8 after the lifting bolt has been removed from the lifting and grout delivering apparatus embedded within the panel; and

FIG. 10 shows the concrete panel of FIG. 9 with grout being pumped through the concrete panel by way of the lifting and grout delivering apparatus to fill the space between the bottom of the panel and the road bed so as to secure the panel in place.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Turning now to the drawings, details are provided of an apparatus which is capable of performing the dual functions of enabling a concrete panel or slab to first be lifted and moved to a construction site and then fixed in place by means of delivering grout to fill a space between the bottom of the panel and a surface (e.g., an excavation, a road bed, or the like) over which the concrete panel is laid. The lifting and grout delivering apparatus herein disclosed has particular application for use during roadway (e.g., freeway) construction and/or repair where a large number of heavy precast concrete panels must be laid end-to-end and side-by-side one another to create a smooth and continuous driveway over which automotive traffic will travel. However, it is to be understood that the apparatus and the method of using this invention are applicable to the construction of any flat surface (such as, for example, an airport runway) to be produced by a series of panels or slabs that are manufactured from concrete or the like and laid over a road bed or a similar support foundation.

Referring initially to FIGS. 1 and 2 of the drawings, there is shown a preferred embodiment for the dual function lifting and grout delivering apparatus 1 to be embedded within a precast concrete panel (designated 30 in FIGS. 3-10) to be used, for example, during the construction and/or repair of a roadway. The apparatus 1 is manufactured from steel or any other suitable durable material that is adapted to resist deformation under heavy loads and tensile forces. A hollow, cylindrical sleeve 3 is affixed to one or more retaining bars 5 and 7. The sleeve 3 has a length that is sufficient to extend completely through the concrete panel 30 from the top to the bottom thereof at the conclusion of the casting process.

The retaining bars 5 and 7 are preferably welded to the sleeve 3. Each of the retaining bars may be, for example, a rebar that is bent around the sleeve 3 so as to extend away therefrom and in opposite directions. The retaining bars 5 and 7 serve as anchors to prevent a displacement of the sleeve 3 during the casting and curing of the concrete panel when the dual function apparatus 1 is being embedded therewithin. Moreover, the retaining bars 5 and 7 affixed to the sleeve 3 cooperate with the rebars (designated 20 in FIGS. 3-10) that are usually embedded within a precast concrete panel to provide structural support in order to hold the apparatus 1 in place as a lifting force is applied to the panel in the manner shown in FIG. 7.

A set of screw threads 9 (best shown in FIGS. 4 and 5) runs around and along the inside of the hollow cylindrical sleeve 3. The screw threads 9 perform dual functions for the lifting and grout delivering apparatus 1. That is, the apparatus 1 includes a threaded end cap 10 to be removably connected to the top of the sleeve 3 at the internal screw threads 9 thereof. As is best shown in FIG. 4, prior to casting the concrete panel 30, the threaded end cap 10 is rotated into mating engagement with the threaded sleeve 3. The end cap 10 stands about 5 cm above the top of sleeve 3 and serves as a detachable plug to prevent the sleeve from being filled with concrete and debris during and after the casting process. A head (e.g., a hex nut) 17 is located at the top of the end cap 10. The head 17 is sized and shaped so as to be engaged by a tool (not shown) to which a rotational force is applied to cause the end cap 10 to be rotated out of its mating engagement with the sleeve 3 once the panel has been cast but before the concrete has had time to fully cure. When the threaded end cap 10 is removed from the threaded sleeve 3, a temporary depression 22 (best shown in FIG. 5) is left in the top of the panel 30 above the sleeve 3. The end cap 10 can be reattached to the sleeve 3 at the end of the casting process.

After the concrete panel 30 has been manufactured and moved to a work site, the panel must be lifted off its transport and moved above the road bed next to one or more adjacent panels. To accomplish the foregoing, the detachable plug 10 is removed from the top of the hollow sleeve 3. By way of a second application for the screw threads 9 inside the cylindrical sleeve 3, a threaded lifting bolt 24 is detachably connected to the threaded sleeve 3 of the lifting and grout delivering apparatus 1 that is embedded within the concrete panel 30 (best shown in

FIG. 6).

More particularly, and referring now to FIGS. 4-8 of the drawings, a conventional hoisting cylinder 26 is laid upon the panel 30 above the gap 22. The threaded lifting bolt 24 is then pushed through the hoisting cylinder 26 and rotated (e.g., by means of an air gun or the like) into mating engagement with the internal screw threads 9 of the threaded sleeve 3 of the lifting and grout delivering apparatus 1. The lifting bolt 24 is preferably long enough so as to extend completely through the sleeve 3. To facilitate the connection (and removal) of the threaded lifting bolt 24 to the screw threads 9 of the sleeve 3, the bolt is preferably covered with grease or a similar lubricant.

With the hoisting cylinder 26 connected to the concrete panel 30 by means of the lifting bolt 24 being mated to the threaded sleeve 3 of the lifting and grout delivering apparatus 1, a crane 50 (of FIGS. 6 and 7) or the like applies a lifting force to the usual hoist coupler 28 that is pivotally connected to the hoisting cylinder 26. The lifting force is transferred to the lifting and grout delivering apparatus 1 via the lifting bolt 24 which creates a lifting point so that the concrete panel 30 can be lifted from its transport, repositioned above and lowered towards the road bed (best shown in FIG. 7). In order to be able to reliably lift and position the concrete panel 30, a lifting and grout delivering apparatus 1 is preferably embedded near each corner of the panel in the manner shown in FIG. 3. Therefore, a total of four lifting and grout delivering apparatus 1 having respective hoisting cylinders 26 and hoist couplers 28 are employed to enable the crane 50 to lift and position the panel. However, it is to be understood that the total number of lifting and grout delivering apparatus embedded within the concrete panel 30 is not to be considered as a limitation of this invention.

Prior to moving the concrete panel 30 to the road bed, a set of corner support blocks or spacers 32 are seated on the road bed to receive thereupon each corner of the panel 30. The corner blocks 32 may be shims that are manufactured from a material (e.g., steel or plastic) capable of supporting the weight of the panel 30. The corner blocks 32 can be shaped and dimensioned as is necessary to elevate the panel 30 above the road bed so as to be level with adjacent concrete panels. After the concrete panel 30 has been lowered towards the road bed and laid on the support blocks 32, the crane 50 is detached from the hoist couplers 28. The lifting bolt 24 is now rotated out of its mating engagement with the threaded sleeve 3, and the hoisting cylinder 26 and hoist coupler 28 are removed from the top of the panel 30. When the panel 30 is laid alongside another panel of a new or a repaired roadway, the panel must be fixed in place to prevent shifting and movement relative to the adjacent panel in response to changing weather conditions and the effect of physical forces to which the panel 30 is exposed over time. By virtue of the hollow sleeve 3 of the apparatus 1 that is embedded therewithin, the panel 30 can be reliably held stationary above the road bed.

When the concrete panel 30 is resting upon the support blocks 32, a space 34 is established between the road bed and the bottom of the panel 30 (best shown in FIG. 9). A urethane grout 36 or any other suitable curable filler material is now pumped down the hollow sleeve 3 from which the lifting bolt 24 was previously removed. Grout 36 may also be pumped down a series of grout pipes 38 (best shown in FIG. 10) that are often embedded within the concrete panel 30 in addition to the lifting and grout delivering apparatus 1. The grout 36 flows through the sleeve 3 and the grout pipes 38 to fill the space 34 below the bottom of the concrete panel 30. The grout 36 is continuously pumped through the panel 30 until the space 34 is completely filled and the corner support blocks 32 are enveloped. When the grout has cured, the concrete panel 30 will be fixed in place above the road bed.

After the grout pumping process has been concluded and the concrete panel 30 is fixed in place as just described, the depression 22 which lies above the sleeve 3 is filled with cement, grout, or the like to create a flat surface across the top of the panel. By virtue of embedding the presently-disclosed lifting and grout delivering apparatus therewithin, additional precast concrete panels can be lifted, positioned, laid end-to-end and/or side-by-side one another, and retained in place to efficiently create a new roadway or repair an existing roadway within less time and with the expenditure of less man hours and cost than had the road bed been precisely graded as is customary in traditional road building techniques. 

1. A method for lifting and transporting a concrete panel to a surface and retaining the panel in place above the surface, said method comprising the steps of: embedding within the concrete panel at least one hollow sleeve that runs through said panel; coupling a lifting bolt to said hollow sleeve; applying a lifting force to said lifting bolt by which the concrete panel is lifted and transported to the surface; uncoupling said lifting bolt from said hollow sleeve after the concrete panel has been transported to the surface; and pumping a curable filler material through said hollow sleeve for receipt below the concrete panel.
 2. The method recited in claim 1, wherein each of said hollow sleeve and said lifting bolt is threaded, said method comprising the additional step of rotating said threaded lifting bolt into mating engagement with said hollow threaded sleeve during the step of coupling said lifting bolt to said sleeve.
 3. The method recited in claim 2, comprising the additional steps of connecting a removable threaded plug to said hollow threaded sleeve below the top of said concrete panel; and removing said threaded plug from said threaded sleeve prior to the step of rotating said threaded lifting bolt into mating engagement with said threaded sleeve.
 4. The method recited in claim 1, comprising the additional steps of laying at least one support block on the surface prior to the step of applying a lifting force to said lifting bolt; seating the concrete panel on said support block when the panel is lifted and transported to the surface, whereby a space is established between the panel and the surface; and filling said space with said curable filler material during the step when said curable material is pumped through said hollow sleeve.
 5. The method recited in claim 4, comprising the additional step of laying a plurality of support blocks on the surface so as to lie below respective ones of the corners of the concrete panel when said panel is transported to the surface and seated on said plurality of support blocks.
 6. The method recited in claim 1, comprising the additional step of attaching at least one retaining bar to said hollow sleeve so that said retaining bar end extends outwardly from said hollow sleeve to anchor said sleeve in place embedded within the concrete panel.
 7. The method recited in claim 6, wherein the concrete panel has a plurality of reinforcement bars embedded therewithin, said method comprising the additional step of positioning said retaining bar attached to said hollow sleeve so as to engage at least some of the plurality of reinforcement bars embedded within the concrete panel to anchor said sleeve in place embedded within the panel.
 8. A method for lifting and transporting a concrete panel to a surface and retaining the panel in place above the surface, said method comprising the steps of: locating at least one spacer on said surface; embedding within opposite sides of the concrete panel a plurality of hollow threaded sleeves that run through the panel; rotating a plurality of threaded lifting bolts into mating engagement with respective ones of said plurality of hollow threaded sleeves; applying a lifting force to said plurality of lifting bolts by which the concrete panel is lifted and transported to the surface; lowering the concrete panel towards the surface until the panel is seated on said spacer so that a space is established between the panel and the surface; rotating said plurality of threaded lifting bolts out of their mating engagement with said plurality of hollow threaded sleeves; and pumping a curable filler material through said plurality of hollow threaded sleeves to fill the space between the concrete panel and the surface on which said spacer is located.
 9. A combination, comprising: a concrete panel having a top and a bottom; an apparatus embedded within said concrete panel and including at least one hollow sleeve extending through said panel between the top and the bottom thereof; a lifting bolt removably coupled to the hollow sleeve of said apparatus embedded within said concrete panel, said lifting bolt being responsive to a lifting force applied thereto by which said concrete panel is lifted and transported to a surface; and a supply of curable filler material to be pumped through said hollow sleeve extending through said concrete panel when said lifting bolt is uncoupled from said sleeve, whereby said curable material is delivered by way of said hollow sleeve between the bottom of said panel and the surface to which said panel is transported.
 10. The combination recited in claim 9, wherein each of said hollow sleeve and said lifting bolt is threaded, said lifting bolt being responsive to a rotational force applied thereto in a first direction by which said threaded lifting bolt is advanced into mating engagement with said hollow threaded sleeve when said lifting bolt is coupled to said sleeve, and said threaded lifting bolt being responsive to a rotational force in an opposite direction to remove said threaded lifting bolt from said hollow threaded sleeve when said threaded lifting bolt is uncoupled from said threaded hollow sleeve.
 11. The combination recited in claim 10, further comprising a threaded plug detachably connected to said threaded hollow sleeve below the top of said concrete panel, said threaded plug being responsive to a rotational force applied thereto by which said plug is detached from said sleeve.
 12. The combination recited in claim 9, further comprising at least one spacer seated on the surface to receive and support said concrete panel above said surface when said panel is lifted and transported to the surface, said spacer establishing a space between the bottom of said concrete panel and the surface to be filled with said supply of curable filler material when said filler material is pumped through said hollow sleeve.
 13. The combination recited in claim 9, said apparatus embedded within said concrete panel also including at least one retaining bar bent around and attached to said hollow sleeve so as to extend outwardly therefrom to anchor said sleeve in place within said concrete panel. 